The software defined network (SDN) concept allows a separation of the control plane from the user or application plane in a communications network. The concept allows the management of network services through abstraction of higher-level functionality. An SDN controller is a logically centralized entity that performs several operations. Those operations include translating the requirements from the SDN application layer down to the SDN datapath or infrastructure layer. The operations further comprise providing the SDN applications with an abstract view of the network (which may include statistics and events). An SDN controller can be leveraged for many enhanced capabilities.
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures.